B3.9 R140LC Engine Water Pump 3286275 For CUMMINS Diesel Engines Parts

1. Working principle of centrifugal pump

Before the pump is started, the pump and the inlet pipe shall be filled with water. After the pump is operated, the water in the impeller channel is thrown around and pressed into the volute under the centrifugal force generated by the high-speed rotation of the impeller. The inlet of the impeller forms a vacuum. The water in the pool is sucked along the suction pipe under the external atmospheric pressure to supplement this space. Then the water sucked in is thrown out by the impeller through the volute and enters the outlet pipe. It can be seen that if the impeller of the centrifugal pump rotates continuously, it can continuously absorb and pressurize water, and water can be continuously lifted from low to high or far away. To sum up, the centrifugal pump is called a centrifugal pump because it lifts water to a high place under the action of the centrifugal force generated by the high-speed rotation of the impeller.

(1) The flow direction of water along the centrifugal pump is along the axial direction of the impeller, and perpendicular to the axial direction, that is, the inlet and outlet flow directions are 90 ° to each other.

(2) Since the centrifugal pump absorbs water in a vacuum by the impeller inlet, it is necessary to inject water into the pump and the suction pipe before starting, or use a vacuum pump to pump air to form a vacuum. Moreover, the pump shell and the suction pipe must be tightly sealed without air leakage, otherwise no vacuum will be formed and no water will be sucked.

(3) Since the absolute vacuum cannot be formed at the inlet of the impeller, the suction height of the centrifugal pump shall not exceed 10m. In addition, the actual allowable installation height (the height between the pump axis and the suction water surface) is far less than 10m due to the loss along the suction pipeline. If the installation is too high, it will not absorb water; In addition, since the atmospheric pressure in the mountainous area is lower than that in the plain, the installation height of the same water pump in the mountainous area, especially in the mountainous area, should be reduced, otherwise it can not absorb water.